Heretofore, as exemplified by the patents to Cienfuegos, U.S. Pat. No. 4,150,851, British, Lurkings #21,497, Danish #53494, Riess, U.S. Pat. No. 510,993, Italian 617,928, Hinrichs, U.S. Pat. No. 3,350,120, Vick 2,644,504, and Forney #2,4l5,479, attempts have been made to make bicycle seats adjustable in height to accommodate different size riders.
Currently bicycle seats are made adjustable by attaching a shaft onto the bottom of the seat and inserting it in the hollow frame, in manner well known in the art. The seats are held in position by means of set screws which engage the shaft. However, it is awkward to readjust the position of the seats. The prior spring actuated devices for changing the height of the sea required the bicycle frame to be redesigned and parts welded to the bicycle frame to install the adjusting spring actuated unit. However since bicycles are made on an assembly line, manufacturers are reluctant to redesign the bicycles for this purpose because of the cost involved. Besides there are millions of bicycles in current use, with conventionally adjustable seats but the owners lack the tools for making the required changes. These bicycle owners offer a potential marke for this invention because persons who have bicycles may want the seats made easily adjustable without making structural changes in the bicycle frame.
What is needed therefore and comprises an important object of this invention is to provide an adjustable seat replacement for the conventional bicycle frame which can be substituted for the existing conventional seat and seat shaft without requiring any structural modification to the existing bicycle frame and thus permit the height of the seat above the frame to be easily adjusted by activating a spring biased plunger.
Basically, this invention comprises a seat height adjusting unit comprising a spring loaded seat shaft and a manual plunger locking device. To install the self adjusting seat of this invention it is only necessary to remove the conventional seat and its shaft, and replace it with the adjustable seat unit described below. No welding or other modification of the bicycle frame is necessary. Owners of bicycles or exercycles can easily and quickly replace their bicycle seats and shafts with the adjustable unit described below.
What is needed therefore and comprises an important object of this invention is to provide a unit comprising a seat and adjustable shaft, which can be inserted inside the tubular frame of the bicycle in place of the usual shaft presently mounted in the tubular frame so the height of the seat can be adjusted.